Enable using the toolchain (llvm) provided FileCheck.

tools/llvm_file_check_wrapper.sh

Index: tools/llvm_file_check_wrapper.sh
diff --git a/tools/llvm_file_check_wrapper.sh b/tools/llvm_file_check_wrapper.sh
new file mode 100755
index 0000000000000000000000000000000000000000..66b571c962aa642a78e08dadf0a10572eae811c1
--- /dev/null
+++ b/tools/llvm_file_check_wrapper.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+# Copyright (c) 2011 The Native Client Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+if [ "$#" -lt 3 ]; then
+    echo "Usage: llvm_file_checl_wrapper <filecheck> <check_file> <cmd_line>"
+    echo "Where:"
+    echo "<filecheck> is the path to FileCheck"
+    echo "<check_file> is a text file containing 'CHECK' statements"
+    echo "<cmd_line> is the command line to use as input to FileCheck"
+    exit 1
+fi
+
+file_check="$1"
+shift
+check_file="$1"
+shift
+what_to_run=$@
+
+$what_to_run | $file_check $check_file